This is no crossbow but a catapult. The defenition of a (cross)bow is that the potential kenetic energy is stored in the elastic limbs of the bow, and not in the elastic string.

Secondly if it were a bow that stores elastic energy in it's limbs, this would be a bow and not a crossbow. Becouse the defenition of a crossbow is a bow mounted on a stave with a mechanical device to hold and release the string. while this device lacks such a stock and triggerdevice.

Actually, you are wrong. The pencil did fly over the building, and it did, in fact, land in the pool. You could not see any waves because (a) they were very small and dissipated before the camera got to the pool; and (b) the camera filmed in very poor quality. To give an idea of how much power this device had, the pencil with the elastic snapped because of the force applied by the elastics. Cheers!

Ignorance, ignorance, ignorance... This is not a crossbow at all. In fact, this is a shortbow on its side. On a full scale size, a bow of any kind can perform better at certain shots, possible aim, and trajectory for beginners I'm not sure exactly how you would make a real crossbow with pencils but you would need more than one pencil. In fact, I'm sure, for a simple crossbow, you would need at least five pencils. One for the stock, one, possibly two, for the lathe, something for a the catch, one for a trigger, and another for a bolt. and thats a simple one... a full one would include a crannequin and stirrup

Yesterday I made a really good crossbow, it doesnt get very good distance, but thats just because i messed up the rubber band and it is kinda loose, but it has a trigger mechanism allowing for easy firing, and I put in a crosshair XD. Im going to post it on instructables soon, when i have the time. By the way, that little crossbow has some insane power for being so small.

It took me two hours including making the video, Instructable, and the bow. I should have been more specific in the video. And try using spell check and proof reading because you contradict yourself. And also, the Launch It contest is over, and I DID win.